There are numerous different designs for knives that have blades that slide longitudinally in the handle into the open position and back into the closed position. These so-called “out-the-front” knives, referred to herein as “OTF” knives, are sometimes mistakenly referred to as “Stiletto” type knives. However, the word “Stiletto” more accurately refers to a type of blade that has dual sharpened edges; Stiletto blades are commonly used in OTF knives.
OTF knives are inherently weaker than folding knives when the blades are in the open or extended position. The primary reason is that folding knives almost always have at least two very strong points of connection or interaction between the blade and the handle. The first point of connection is the highly secure connection between. the handle and the blade at the blade pivot point. The second point of connection is between the tang of the blade and a blade stop pin in the handle that contacts the tang of the blade and stops the blade's rotation when the blade is rotated into the open position. These two strong connections between the handle and the blade result in folding knives that have very strong blade-to-handle connections. What's more, many folding knives add a third strong point of connection between the blade and the handle: a lock that secures the blade in the open position and which must be disengaged to move the blade into the closed or folded position. It will be appreciated therefore that regardless of whether a folding knife has two or three of these connection points or “lands”, the blade is very securely attached to the handle. The result is that the blade is very securely held in the open position with a minimal amount of blade wobble relative to the handle.
An OTF knife completely lacks the primary stabilizing feature of folding knives: the pivot axis. Indeed, in almost all OTF knives the blade travels freely in the handle at least at some point during both the opening and closing motions. As a result, OTF knives are notoriously weak and the blades are very prone to wobble when the blade is in the open position. Although OTF knives include locks to secure the blade in the open position, the locks tend to provide relatively little support for the blade. Typically, there are only one and at most two points of interconnection or lands between the handle and the blade. The result is that most OTF knives are little more than novelties, ill suited for tactical operations and serious work that requires a strong knife.
OTF knives generally use a spring-loaded mechanism to drive the blade from the closed to the open position. There are two basic spring mechanisms used in OTF knives. The first is sometimes called a “shuttle” system. These systems use a trigger to load the spring force that is applied to the blade. The second common system is uses a “mechanical” reload system that is similar in design to a crossbow. With these systems, the user manually loads the spring and that load is transferred to the blade when a trigger is activated. Typically, the trigger mechanism in an OTF is located to one side or the other of the spring mechanism. As a result, when the blade is driven into the open position it actually travels through a serpentine path. This causes unwanted wear on parts, including the sharpened edges of the blade.
With many OTF designs, the mechanism that locks the blade open not only is inherently weak as noted above, but also fails to correctly lock the blade in the open position, resulting in a misfire. When an OTF misfires, the blade is driven toward the open position but fails to lock, resulting in a dangerous situation. A misfire may also occur in the retracting direction with OTF knives that automatically retract the blade. A misfire when retracting the blade can obviously present a dangerous situation.
The present invention relates to an OTF knife that provides three points of interconnection between the handle and the blade when the blade is in the open position, resulting in an extremely strong blade/handle connection. The blade is driven to the open position with a firing spring. A separate retraction spring provides spring tension on the blade to automatically drive it from the open position into the stowed position in the handle. Latching and firing mechanisms interact with a trigger to lock and unlock the blade in both the open and closed positions. The latch mechanism includes a timing function to correctly time when the blade opens and closes.
The OTF knife of the present invention provides an extremely strong interconnection between the handle and the blade, and the latching and firing mechanisms prevent misfires.